Problem: Express your answer as a mixed number simplified to lowest terms. $3\dfrac{7}{20}-2\dfrac{5}{20} = {?}$
Answer: Separate the whole numbers from the fractional parts: $= {3} + {\dfrac{7}{20}} - {2} - {\dfrac{5}{20}}$ Bring the whole numbers together and the fractions together: $= {3} - {2} + {\dfrac{7}{20}} - {\dfrac{5}{20}}$ Subtract the whole numbers: $=1 + {\dfrac{7}{20}} - {\dfrac{5}{20}}$ Subtract the fractions: $= 1+\dfrac{2}{20}$ Combine the whole and fractional parts into a mixed number: $= 1\dfrac{2}{20}$